Question

因此,这是一个真正简单的问题。我试图利用ema虫来防止种族状况。我尝试阅读这些单页,但确实令人困惑。难道有人可以简单地解释他们如何工作?

Answer 1

I assume you are using in Linux/Unix. Semaphores are used to control/restrict the access to a shared resource (lets say a global variable) from multiple threads. One Thread can take semaphore, modify the value and release it If another thread tries to access the variable, it should acquire the semaphore, if its already aquired, it is pended and gains access after the previous thread relinquishes control.

这样,甲型磷就被用于排序作业和变数的完整性。

Semaphores are also used to signal events from one thread to another. Mutex are variants of semaphore, where the same thread acquires and release it (to protect critical section or race conditions)

更正

Answer 2

我目前正在我的系统二类中讨论这个议题,该类基本上使用C语文编制方案。正如我的教员向我们解释的那样,一种麻.症是一种非负面的ger化同步变量,它基本上有助于控制某些阅读功能。我知道,这在某种程度上模糊不清,但所有内心的恐惧都被用来规范read活动,特别是在利用相对较小的缓冲器时。我希望我会把你召集起来(0-0)。

A couple of examples of what I mean:

• 失眠:非负面的消化同步变量。

• sem_wait(s):[在(s=0)等待期间; s-;]——原称P(),荷兰语“Proberen”(考试)

• sem_post(s): [ s++; ]

– Originally named V(), Dutch for "Verhogen" (increment)

– OS guarantees that operations between brackets [ ] are executed indivisibly.

CREDIT/CITATION:Phillips博士,Joseph,DePaul大学,讲师(2014年)

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